Display system, reception device, display device and communication connection method

1. A display system comprising:

a transmission device that transmits image data;

a reception device that is connected to said transmission device and receives the image data; and

a display device that displays an image indicated by the image data received by said reception device, wherein:

said reception device creates a connection code, and creates a security key from the connection code, the security key being used to connect with said transmission device,

said display device displays the connection code;

said transmission device creates the security key from the connection code having been inputted, and is connected to said reception device by using the security key;

when utilization by all transmission devices that are connected to said reception device has been terminated, said reception device creates a new connection code to update the security key and causes the display device to display the new connection code after disconnecting the all transmission devices;

the state where the image is displayed by said display device is astate where said reception device is used by said transmission device; and

the state where the utilization of said reception device has been terminated by said transmission device is a state where transmission of the image data from the all connected transmission devices are stopped and where the image is not displayed by said display device.

2. The display system according to claim 1 , wherein, when utilization by the all transmission devices that are connected to said reception device have been terminated, after a predetermined grace time has elapsed, said reception device creates a new connection code to update the security key.

3. A reception device comprising:

a communication unit that is connected to a transmission device transmitting image data and that receives the image data;

a connection code creator that creates a connection code;

a security key creator that creates a security key from the connection code, the security key being used to connect with the transmission device; and

a display output unit that outputs the connection code, wherein:

when utilization by all connected transmission devices has been terminated, said connection code creator creates a new connection code, said display output unit outputs the new connection code created by said connection code creator to a display device and causes the display device to display the new connection code, said security key creator updates the security key from the new connection code created by said connection code creator, after the all transmission devices are disconnected;

the state of displaying image indicated by image data is a state where said reception device is used by said transmission device; and

the state where the utilization of said reception device has been terminated by said transmission device is a state where transmission of the image data from the all connected transmission devices are stopped and where the image is not displayed by said display device.

4. The display system according to claim 1 , wherein, in the utilization, the transmission device uses functions of the reception device including transmitting the image data included in transmission device to the reception device and causing the reception device to output the image data to the display device.

5. The display system according to claim 1 , wherein a start of the utilization includes transmission of the image data from the transmission device to the reception device.

6. The display system according to claim 1 , wherein the termination of the utilization of said reception device includes a complete stop of the image data transmission from the transmission device.

7. The reception device according to claim 3 , wherein, in the utilization, the transmission device uses functions of the reception device including transmitting the image data included in transmission device to the reception device and causing the reception device to output the image data to the display output unit.

8. The reception device according to claim 3 , wherein a start of the utilization includes transmission of the image data from the transmission device to the reception device.

9. The reception device according to claim 3 , wherein the termination of the utilization of said reception device includes a complete stop of the image data transmission from the transmission device.

10. A communication connection method comprising:

creating a connection code;

displaying the connection code;

connecting to a transmission device to which the connection code has been inputted;

receiving image data transmitted from the transmission device; and

updating comprising, in a case where utilization by all connected transmission devices has been terminated, creating and displaying a new connection code, after disconnecting the all transmission devices, wherein:

the state of displaying image indicated by image data is a state of being used by said transmission device; and

the state where the utilization has been terminated by said transmission device is a state where transmission of the image data from the all connected transmission devices is stopped and where the image is not displayed.

11. The communication connection method according to claim 10 , wherein, in said connecting, in a case where a security key created from the connection code having been inputted to the transmission device coincides with a security key created from the connection code in said creating, connection to the transmission device is made.

12. The communication connection method according to claim 10 , wherein the utilization includes transmitting the image data included in the transmission device to a reception device and causing the reception device to output the image data for displaying the connection code.

13. The communication connection method according to claim 12 , wherein a start of the utilization includes transmission of the image data from the transmission device to the reception device.

14. The communication connection method according to claim 12 , wherein the termination of the utilization of said reception device includes a complete stop of the image data transmission from the transmission device.